This invention relates to the art of well services, and more particularly to a user friendly interactive computer system, to aid an engineer in selecting a proper treatment fluid for a particular situation. This interactive computer system, also called xe2x80x9cthe Advisorxe2x80x9d in the remaining part of this specification is typically used in the art of constructing and stimulating subterranean wellbore for water or hydrocarbons production.
In the art of wellbore services, numerous treatment fluids are pumped into the well and eventually into the formation. For instance, fracturing fluids are pumped to create a conductive flow path for the hydrocarbons trapped in the formation and thus facilitate enhanced recovery of the same. Fracturing fluids are required to initiate and propagate a fracture to its desired length, and provide necessary width and viscosity to transport, and efficiently place proppant inside the fracture.
The desired fluid properties are obtained through a combination of additives such as polymeric additives used for controlling the viscosity. However, the fluid composition may somehow be altered during the treatment. For instance, during the job execution most of the polymeric fluids have a tendency to dehydrate due to the phenomenon known as fluid loss, thus resulting in higher concentrations of polymer inside the proppant pack. This can hinder the movement of hydrocarbons inside the fracture. To ensure a proper clean up the fluid must be adequately loaded with ample amount of breakers to enable proper disintegration of polymers.
The above example is just an example showing that selection of proper treatment fluids mainly involves a delicate balance between the basic fluid requirements such as adequate viscosity, stability at higher temperatures, lower friction pressures, low fluid leak off coefficients, etc. and fluid properties that may be detrimental to the job such as tendency to form emulsions, shear degradation, high initial stresses, improper clean-up f the pack, etc. A wide range of parameters pertaining to formation and fluid characteristics need to be evaluated in order to arrive at an optimum fluid design. Some of these parameters are independent and some work in conjunction with another and can alter the affect of one another if they co-exist. This leads to several possible combinations and to carry out analysis of each in the limited decision making time is humanly impossible. This may result in a tendency to selecting or pumping the fluids that have xe2x80x9ctraditionallyxe2x80x9d enabled proper execution of job and have helped in xe2x80x9creasonablexe2x80x9d recovery of the hydrocarbons after the job, thus leaving little room for improvement or allowing introduction of latest technology.
Moreover, the well services industry typically operates in relatively remote locations. Though the use of modern communications tools such as Internet has greatly enhanced the possibility of exchanging information with distant experts, it would be often beneficial to appeal to their expertise even for ordinary operations.
Therefore it would be suitable to provide a convenient tool to aid in selecting a fluid appropriate for a given situation while taking advantage of experts"" knowledge. Such a tool also could be helpful for training new entrants and by providing concise statements validating a selection and/or a non-selection of other candidates.
The invention is an interactive computer system for providing help in selecting a well-services treatment fluid, the system comprising a act of fluid families, a set of relevant fluid characteristics and a set of digital ratings of each fluid family with regard to these characteristics. The Advisor further includes a set of job parameters pertaining to the treatment and qualitative ratings of said parameters estimating their relevance in the effective success of a treatment. An interface allows the user to enter the job parameters values known to him. Built in rules, associated with calculating means such as an integrated spreadsheet, match fluid characteristics and job parameters and trigger the elimination of fluids that are not compatible with some value of the job parameters and compute a confidence index for the non-eliminated fluid families, said confidence index based on the sum of the products of the fluid families digital ratings and on the rating of the known job parameter. The Advisor also includes means to display the results.
According to a preferred aspect of the invention, experts provide at least a list of fluid characteristics and a list of job parameters that affect the selection of a fluid family, as well as the ratings of the relative importance of these parameters and the matching and filtering rules. This is indeed an important aspect of the invention to ensure for instance that users will not overlook key criteria of rare occurrence. The specific fluid characteristics are preferably entered also through the control of experts but not necessarilyxe2x80x94provided that all fluid characteristics are provided.
Fluids used in well services are suitable within a limited temperature range. Comparing that useful temperature range and the bottomhole temperature of the well is indeed the first filter of suitability of any fluid family and indeed, no recommendation can be made unless the bottomhole temperature of the well is known.
For most applications including, for instance, selecting a fluid family appropriate for a fracturing operation, all other job parameters may remain unknown, and the system will still provide a selection of suitable fluid families based on the temperature of use. However in this later case, the confidence index will be low. Moreover, according to a preferred embodiment of the present invention, where some of the unknown parameters could have triggered the elimination of certain fluid families, a warning message is displayed. With any job parameter added to the system, the confidence index will increase.